What is 123 series ru?

As an AI language model, I am unsure about the specific context of 123 series RU. However, the term "RU" is an abbreviation for Russia, which suggests that the 123 series could be a product or service related to the country. It is possible that the 123 series could refer to a range of products, such as electronic devices, automobiles, or even a television series. Without further information, it is difficult to provide more details about the 123 series RU.